In أُولُو، أُولِي، أُولَاتُ، أُولَاتِ, keep the written و after the initial hamza. Do not give it a separate consonantal “w” sound, but do not omit it in spelling.
أُولَئِكَ is mentioned only as a spelling comparison for this written و; it is a demonstrative, not a form of ذُو.
Correct spelling: أُولُو عِلْمٍ. Incorrect spelling: أُلُو عِلْمٍ.